Pin and rail assembly



y 22, 9 MASARU KONDO 3,456,545

PIN AND RAIL ASSEMBLY Filed April 1, 1968 BY B" a in United States Patent O 3,456,545 PIN AND RAIL ASSEMBLY Masaru Kondo, Hamamatsu-shi, Japan, assignor to Nippon Gakki Seizo Kabushiki Kaisha, Hamamatsu-shi, Japan, a corporation of Japan Filed Apr. 1, 1968, Ser. No. 717,651 Claims priority, application Japan, Apr. 7, 1967, 42/ 22,223 Int. Cl. (21% 3/12 U.S. Cl. 84-435 3 Claims ABSTRACT OF THE DISCLOSURE A pin and rail assembly included in the key-board system of a piano comprises a channeled metal rail having a plurality of holes spatially disposed lengthwise on the top thereof, a plurality of pins vertically disposed in the channel of the metal rail in a manner to penetrate the rail half way through the holes, and curable synthetic resinous materials initially filled into the channel in the liquid form and solidified so as to fix one end of the pins at the desirable position in the channel.

This invention relates to a pin and rail assembly included in the key-board system of a piano, and more particularly to a pin and rail assembly improved so as to keep the rail free from the effect of bending and torsion.

The prior art rails such as a balance rail and front rail were formed from a sufficiently dried wooden material, but were inevitably subjected to the effect of bending and torsion caused by such factors as temperature and humidity prevailing where the piano was situated.

Though it has been proposed to employ a metal member as a rail instead of a wooden material, such metal member resulted in a heavier rail tha a wooden one, causing greater difficulties in setting pins on the rail.

An object of this invention is to provide a pin and rail assembly improved in such a manner that the rail, though made of metal material, is not, as a Whole, substantially heavy as compared with that of a wooden one, but is further protected from the effect of bending and torsion due to its metal material, and that pins can be easily fitted into the rail.

In an aspect of this invention, a pin and rail assembly comprises a channeled metal rail having a plurality of holes spatially disposed lengthwise on the top thereof, a plurality of pins vertically disposed in the channel of the metal rail in a manner to penetrate the rail half way through the holes, and curable synthetic resinous materials initially filled into the channel in the liquid form and solidified so as to fix one end of the pins at the desirable position in the channel.

In this case, the metal rail may be either a single or double channel type. The curable synthetic resinous material may consist of thermosetting synthetic resin such as epoxy resin and polyester resin, or a mixture of polyester resin, glass fiber composed of short filaments and calcium carbonate so as to have a thermal expansion coefficient closely resembling that of the metal employed in the rail.

This invention will be understood more clearly from the following description by reference to the accompanying drawing.

FIG. 1 is a perspective view of a part of the pin and rail assembly embodying the invention; and

3,456,545 Patented July 22, 1969 FIG. 2 is a sectional view of the pin and rail assembly according to another embodiment of the invention.

FIG. 1 indicates a pin and rail assembly having a double channel type metal rail 1 employed as a balance rail or front rail included in the key-board system of a piano. The rail 1 is preferably formed from a thin aluminum plate, and has a plurality of holes 2 spatially disposed lengthwise on two elongated top surfaces 3 thereof. The pin and rail assembly further includes a plurality of pins 4 vertically disposed in the channel 1a of the rail 1 in a manner to penetrate the top surfaces 3 of the rail 1 half way through the holes 2 and then fixed at a portion which is deformed or crimped-to reduce the diameter. of the hole 2. The pin and rail assembly also comprises curable synthetic resinous materials 5 initially filled intothe channel in the liquid form after adjusting the position of the pins and then solidified so as rigidly to support the lower half of the pins inserted into the channel. The pins arranged on one of the top surfaces carry white keys (not shown) and those arranged on the other carry black ones (also not shown).

In this case, the pins may be disposed in the rail by forcedly inserting them into a triangular or rectangular hole instead of fixing them at the aforementioned deformed or crimped portion.

FIG. 2 indicates a pin and rail assembly having a single channel type metal rail 11. When it is desired to employ a balance rail, two parallel rails 11 are bridged over a series of key frames (not shown). In this arrangement, a protrusion 12 is integrally formed on both edges of the top of the rail 11 in a manner to rise upwardly therefrom. After fitting pins 13 into the rail 11, an upper channel defined by both protrusions is filled with curable synthetic resin. The resin is solidified so as rigidly to secure the pins in place with the aid of the solidification of the synthetic resin filled into another channel 14 of the same shape as that of the foregoing pin and rail assembly of FIG. 1.

What is claimed is:

1. A pin and rail assembly included in the key-board system of a piano comprising a channeled metal rail having a plurality of holes spatially disposed lengthwise on the top thereof, a plurality of pins vertically disposed in the channel of the metal rail in a manner to penetrate the rail half way through the holes, and curable synthetic resinous materials initially filled into the channel in the liquid form and solidified so as to fix one end of the pins at the desirable position in the channel.

2. A pin and rail assembly claimed in claim 1 in which the channeled metal rail has protrusions integrally formed in a manner to rise from both edges of the top thereof so as to define a separate channel thereon.

3. A pin and rail assembly claimed in claim 1 in which the channeled metal rail is of a double channel type.

References Cited UNITED STATES PATENTS 2,764,907 10/1956 Link 84-423 2,934,989 5/1960 Belli et al. 84-411 3,087,368 4/1963 Lund 84-423 RICHARD B. WILKINSON, Primary Examiner LAWRENCE R. FRANKLIN, Assistant Examiner US. Cl. X.R. 84-452 

